/*
 * This code implements the MD5 message-digest algorithm.
 * The algorithm is due to Ron Rivest.  This code was
 * written by Colin Plumb in 1993, no copyright is claimed.
 * This code is in the public domain; do with it what you wish.
 *
 * Equivalent code is available from RSA Data Security, Inc.
 * This code has been tested against that, and is equivalent,
 * except that you don't need to include two pages of legalese
 * with every copy.
 *
 * To compute the message digest of a chunk of bytes, declare an
 * MD5Context structure, pass it to MD5Init, call MD5Update as
 * needed on buffers full of bytes, and then call MD5Final, which
 * will fill a supplied 16-byte array with the digest.
 *
 * Changed so as no longer to depend on Colin Plumb's `usual.h' header
 * definitions; now uses stuff from dpkg's config.h.
 *  - Ian Jackson <ijackson@nyx.cs.du.edu>.
 * Still in the public domain.
 */

#include <string.h>		/* for memcpy() */
#include <sys/types.h>		/* for stupid systems */

#ifndef WIN32
#include <netinet/in.h>		/* for ntohl() */
#endif

#include "rutil/vmd5.hxx"

/* Add _BIG_ENDIAN for Solaris */
/* Add _BIG_ENDIAN__ for MAC OSX */
#if defined(WORDS_BIGENDIAN) || defined(_BIG_ENDIAN) || defined( __BIG_ENDIAN__ ) || (defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)) || defined(RESIP_BIG_ENDIAN)
void
resip::byteSwap(u_int32_t *buf, unsigned words)
{
   md5byte *p = (md5byte *)buf;

   do
   {
      *buf++ = (u_int32_t)((unsigned)p[3] << 8 | p[2]) << 16 |
         ((unsigned)p[1] << 8 | p[0]);
      p += 4;
   }
   while (--words);
}
#else
#define byteSwap(buf,words)
#endif


/*
 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 * initialization constants.
 */
void
resip::MD5Init(struct MD5Context *ctx)
{
   ctx->buf[0] = 0x67452301;
   ctx->buf[1] = 0xefcdab89;
   ctx->buf[2] = 0x98badcfe;
   ctx->buf[3] = 0x10325476;

   ctx->bytes[0] = 0;
   ctx->bytes[1] = 0;
}

/*
 * Update context to reflect the concatenation of another buffer full
 * of bytes.
 */
void
resip::MD5Update(struct MD5Context *ctx, md5byte const *buf, unsigned len)
{
   u_int32_t t;

   /* Update byte count */

   t = ctx->bytes[0];
   if ((ctx->bytes[0] = t + len) < t)
      ctx->bytes[1]++; 	/* Carry from low to high */

   t = 64 - (t & 0x3f); 	/* Space available in ctx->in (at least 1) */
   if (t > len)
   {
      memcpy((md5byte *)ctx->in + 64 - t, buf, len);
      return ;
   }
   /* First chunk is an odd size */
   memcpy((md5byte *)ctx->in + 64 - t, buf, t);
   byteSwap(ctx->in, 16);
   MD5Transform(ctx->buf, ctx->in);
   buf += t;
   len -= t;

   /* Process data in 64-byte chunks */
   while (len >= 64)
   {
      memcpy(ctx->in, buf, 64);
      byteSwap(ctx->in, 16);
      MD5Transform(ctx->buf, ctx->in);
      buf += 64;
      len -= 64;
   }

   /* Handle any remaining bytes of data. */
   memcpy(ctx->in, buf, len);
}

/*
 * Final wrapup - pad to 64-byte boundary with the bit pattern 
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
void
resip::MD5Final(md5byte digest[16], struct MD5Context *ctx)
{
   int count = ctx->bytes[0] & 0x3f; 	/* Number of bytes in ctx->in */
   md5byte *p = (md5byte *)ctx->in + count;

   /* Set the first char of padding to 0x80.  There is always room. */
   *p++ = 0x80;

   /* Bytes of padding needed to make 56 bytes (-8..55) */
   count = 56 - 1 - count;

   if (count < 0)
   {	/* Padding forces an extra block */
      memset(p, 0, count + 8);
      byteSwap(ctx->in, 16);
      MD5Transform(ctx->buf, ctx->in);
      p = (md5byte *)ctx->in;
      count = 56;
   }
   memset(p, 0, count);
   byteSwap(ctx->in, 14);

   /* Append length in bits and transform */
   ctx->in[14] = ctx->bytes[0] << 3;
   ctx->in[15] = ctx->bytes[1] << 3 | ctx->bytes[0] >> 29;
   MD5Transform(ctx->buf, ctx->in);

   byteSwap(ctx->buf, 4);
   memcpy(digest, ctx->buf, 16);
   memset(ctx, 0, sizeof(*ctx)); 	/* In case it's sensitive */
}

#ifndef ASM_MD5

/* The four core functions - F1 is optimized somewhat */

/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f,w,x,y,z,in,s) \
(w += f(x,y,z) + in, w = (w<<s | w>>(32-s)) + x)

/*
 * The core of the MD5 algorithm, this alters an existing MD5 hash to
 * reflect the addition of 16 longwords of new data.  MD5Update blocks
 * the data and converts bytes into longwords for this routine.
 */
void
resip::MD5Transform(u_int32_t buf[4], u_int32_t const in[16])
{
   u_int32_t a, b, c, d;

   a = buf[0];
   b = buf[1];
   c = buf[2];
   d = buf[3];

   MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
   MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
   MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
   MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
   MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
   MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
   MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
   MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
   MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
   MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
   MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
   MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
   MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
   MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
   MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
   MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);

   MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
   MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
   MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
   MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
   MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
   MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
   MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
   MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
   MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
   MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
   MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
   MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
   MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
   MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
   MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
   MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

   MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
   MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
   MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
   MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
   MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
   MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
   MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
   MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
   MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
   MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
   MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
   MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
   MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
   MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
   MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
   MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);

   MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
   MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
   MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
   MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
   MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
   MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
   MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
   MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
   MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
   MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
   MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
   MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
   MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
   MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
   MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
   MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);

   buf[0] += a;
   buf[1] += b;
   buf[2] += c;
   buf[3] += d;
}

#endif

/* ====================================================================
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